Pityriasis lichenoides-like drug reaction: A clinical histopathologic study of 10 cases.

BACKGROUND: Lymphomatoid drug reactions can mimic endogenous T and B cell lymphoproliferative diseases.

OBJECTIVES: We present a novel form of cutaneous drug reaction with features of pityriasis lichenoides (PL), a recognized form of T cell dyscrasia.

METHODS: Ten cases were studied where a cutaneous eruption exhibiting semblance to PL within a few weeks to months after starting a particular drug.

RESULTS: The patient cohort comprised 7 females and 3 males with the mean age of 60 years. Widely distributederythematous cutaneous lesions were present in 6 cases whereas a more localized distribution was seen in three cases. The most frequently implicated drugsassociated with the eruption were antidepressants and statins. Histologic examination showed a morphologic picture identical to PL including marked epitheliotropism of mildly atypical lymphocytes, psoriasiform epidermal hyperplasia, dyskeratosis, hemorrhage, and a thick parakeratotic scale. Therewas a significant reduction in the expression of CD7 and CD62L amid the T cells. Regression of the eruption occurred in all cases excluding one.

CONCLUSION: Thefindings conform the categorization of this process as a form of T-cell dyscrasia albeit one that is reversible, dependent on the drug withdrawal. The limitationof our study includes the retrospective design of the study.